where \(\omega _b\)  is a free parameter, we take \(\omega _b=0.4\pm 0.04 (0.5\pm 0.05)\)  GeV for \(B(B_s)\)  meson in numerical calculations, and \(N_B=101.445(N_{B_s}=63.671)\) 
is the normalization factor for \(\omega _b=0.4(0.5)\) . These parameters has been fixed using the rich experimental data on the
\(B_{(s)}\)  decay channels. In this model the significant feature is the intrinsic transverse momentum dependence, which is essential for the \(B_{(s)}\)  meson.
It can It can provide additional suppression in the large \(b\)  region, where the soft dynamics dominates and Sudakov
suppression is weaker. Considering a small SU(3) breaking, the \(s\)  quark momentum fraction is a litter larger than that of the \(u(d)\)  quark in the lighter \(B\)  meson, because of the heavier
mass for the \(s\)  quark. From the shape of the distribution amplitude shown in Ref.[1]}, it is easy to see that the larger \(\omega _b\)  gives a larger momentum fraction
to the \(s\)  quark.
